1500万年前现代多样性梯度的起源
现代多样性梯度的起源是1500万年前，这一成果由英国牛津大学Saupe, Erin E.研究组经过不懈努力而取得。相关论文于2023年2月15日发表在《自然》杂志上。
该课题组研究人员以高时空分辨率量化了过去4000万年浮游有孔虫中纬度多样性梯度的出现，发现现代风格的梯度仅出现在1500万年前。空间和时间模型表明，浮游有孔虫的纬度多样性梯度可能受水柱物理结构的控制。在1500万年前，随着低纬度垂直温度梯度的增加，纬度温度梯度的陡化可能增强了生态位划分，并为低纬度物种形成提供了更多机会。
为了支持这一假设，该团队发现低纬度物种形成率越高，多样性梯度越陡峭，这与浮游有孔虫深度划分的时空模式一致。高纬度物种的灭绝也增强了纬度多样性梯度，但这种影响往往弱于物种形成。他们的结果为理解海洋纬度多样性梯度在长时间尺度上的演化提供了一个步骤。
据了解，纬度多样性梯度(LDG)是现代生态系统在不同支系的普遍特征。一个多世纪以来，纬度多样性梯度的成因机制一直存在争议，部分原因是许多假定的驱动因素同时与纬度共变。过去为解开纬度多样性梯度机制提供了机会，因为生物多样性、纬度和可能的因果因素之间的关系随时间而变化。
附：英文原文
Title: Origination of the modern-style diversity gradient 15 million years ago
Author: Fenton, Isabel S., Aze, Tracy, Farnsworth, Alexander, Valdes, Paul, Saupe, Erin E.
Issue&Volume: 2023-02-15
Abstract: The latitudinal diversity gradient (LDG) is a prevalent feature of modern ecosystems across diverse clades. Recognized for well over a century, the causal mechanisms for LDGs remain disputed, in part because numerous putative drivers simultaneously covary with latitude. The past provides the opportunity to disentangle LDG mechanisms because the relationships among biodiversity, latitude and possible causal factors have varied over time. Here we quantify the emergence of the LDG in planktonic foraminifera at high spatiotemporal resolution over the past 40 million years, finding that a modern-style gradient arose only 15 million years ago. Spatial and temporal models suggest that LDGs for planktonic foraminifera may be controlled by the physical structure of the water column. Steepening of the latitudinal temperature gradient over 15 million years ago, associated with an increased vertical temperature gradient at low latitudes, may have enhanced niche partitioning and provided more opportunities for speciation at low latitudes. Supporting this hypothesis, we find that higher rates of low-latitude speciation steepened the diversity gradient, consistent with spatiotemporal patterns of depth partitioning by planktonic foraminifera. Extirpation of species from high latitudes also strengthened the LDG, but this effect tended to be weaker than speciation. Our results provide a step change in understanding the evolution of marine LDGs over long timescales.
DOI: 10.1038/s41586-023-05712-6
Source: https://www.nature.com/articles/s41586-023-05712-6
来源：科学网 小柯机器人